Gastrointestinal functions may not operate properly for various reasons, including illness, disease, treatments involving pain killing drugs or anesthesia associated with a surgical procedure. Air swallowed by the patient can also contribute to gastrointestinal malfunctions because the gas is not efficiently passed through the digestive tract. Abdominal distention can result causing not only bowel function impairment and interference with the absorption of nutrients through the bowel, but also may prevent the patient from breathing deeply or coughing properly, perhaps leading to pulmonary difficulties. Not only does the patient suffer significant pain from abdominal distention, but also with reduced bowel absorption, the patient may become undernourished thereby impeding recovery from disease or surgery.
Various nasogastric aspirator devices have been developed in an effort to avoid abdominal distention. One such device is composed of two different diameter side-by-side tubes, the larger tube having several holes in the distal end for entry of stomach fluids and solids. A suction source is attached to the proximal end of the larger tube. The proximal end of the smaller tube is vented to the atmosphere whereas the distal end of the smaller tube is connected in fluid flow communication with the distal end of the larger tube. This type of nasogastric aspirating device as well as others previously developed often become clogged from stomach phlegm, food or the stomach tissue itself, all of which can block the entrances to the larger aspirator tube or the communicating passage between the smaller and larger tubes. As a result, abdominal distention occurs.
Surgical invasion of a body part generally results in trauma to the part and often an accumulation of body fluids from the tissue itself or from various body fluid systems. In addition, the surgical invasion generally creates a variety of debris, including small portions of tissue and bone, coagulated blood, irrigation fluids, and the like. Normally, it is advantageous to remove such debris and fluids from the surgical site. Accordingly, aspirators and catheters of various types have been developed to remove this material.
A large majority of these wound drain catheters comprise a drain section for fluid communication with the wound and a separate outflow or extension tube for carrying the fluid from the drain section to a reservoir. In some wound drain catheters, the drain section includes a length of tubing that is perforated by forming small apertures through the tubing wall. One significant problem that has been encountered with this type of wound catheter is that the perforations can easily become occluded by the debris remaining from the surgical invasion of the body part. Occlusion can also occur when the body cavity walls collapse around the catheter. When occlusion takes place, it diminishes the efficiency of draining and aspiration or halts it altogether.
Another problem with the perforated wound drainage catheters of the prior art is that living tissue can also be torn away and sucked into the relatively unobstructed perforations, depending upon their size and the degree of suction force used. This can result in additional trauma to the patient and a longer recovery period.
A number of prior art patents disclose wound drain catheters that attempt to solve the above and other problems. Some representative patents in this art are described as follows:
Blake et al., U.S. Pat. No. 4,398,910 and Blake et al., U.S. Pat. No. 4,465,481 disclose wound drain catheters comprised of a fluted drain portion connected by a connector to an outflow tube portion. A preferred embodiment of the drain portion includes a solid core having a longitudinal axis. A plurality of evenly spaced elongated strut portions project radially outward from the core and run along the drain portion. Each strut portion has a generally T-shaped cross section, with the base of the T secured to the core. Each set of adjacent strut portions forms an external lumen that opens through a slot or groove that is formed between adjacent overhand portions of the strut portions. Fluid may be suctioned from a wound through the external lumens traveling the length of the drain portion and entering the outflow portion within a connector.
Ekbladh et al., U.S. Pat. No. 4,445,897, discloses a catheter for draining surgical wounds which includes a hollow catheter tube with a central longitudinal lumen formed therein. One end of the catheter is designed to be connected to a suction source. Two longitudinally extending and diametrically opposed slots are formed in the outer wall of the tip or distal end portion of the tube. The slots widen inwardly to form two external lumens. A plurality of through openings in the base of the external lumens place the external lumens in fluid communication with the inner lumen.
LeVeen et al., U.S. Pat. No. 4,650,463 discloses perforated tubing for use in surgical drains. In the preferred embodiment, a tube body includes a central lumen having a cloverleaf shape cross section. The outer cross-sectional perimeter of the tube conforms to this cloverleaf cross section. Each set of adjacent cloverleaf portions of the tube define an external longitudinal lumen groove. The external lumen grooves open through elongated slots. A plurality of perforations are formed in the bottoms of the longitudinal lumen grooves and place the grooves in fluid flow communication with the central lumen.
U.S. Pat. Nos. 2,930,378, 3,020,913, 4,531,935, 4,543,089 and 4,573,965 disclose a variety of hollow tubular sections with radial openings formed therein for placing the exterior of a tube in fluid communication with an internal lumen formed therein.
In spite of the above approaches to providing catheters or aspirators for draining body cavities, viscera, and wounds, there has remained a need for new and improved methods for such drainage, particularly methods which minimize or eliminate the problem of occlusion of perforations in a tube by debris in a wound or intact living tissue in a body cavity or viscus during drainage or aspiration.